Field of the Invention
The present invention generally relates to a micro-electron column including nanostructure tips that have a tubular, columnar, or blocky structure ranging in size from several nanometers to dozens of nanometers. More particularly, the present invention relates to a micro-electron column including nanostructure tips that can easily emit electrons because a high electric field is generated at the end of the nanostructure tips when a voltage is applied thereto, the micro-electron column being capable of having improved performance by helping the electrons emitted from the nanostructure tips to enter a part of an electron lens, namely an aperture of the electron lens.
Description of the Related Art
The micro-electron column relating to the present invention, which is based on an electron emitter and the micro-structural electro-optical components operated under the basic principle of a scanning tunneling microscope (STM), was initially introduced in the 1980's. The micro-electron column is configured such that micro parts are assembled elaborately to minimize optical aberration, thereby realizing an improved electron column. Further, the micro-electron column that is small in size can be efficiently used for a multi-electron column by arranging a plurality of electron columns in parallel or in series. Accordingly, the micro-electron column is being applied to devices that use an electron beam, such as electron microscopes, as well as manufacture devices or inspection devices, which are used in the semiconductor industry or display industry.
FIG. 1 is a view illustrating a structure of a micro electron column, wherein an electron beam is scanned by aligning an electron emitter, a source lens, a deflector, and an einzel lens as a focus lens, in a column.
Generally, a microcolumn, as a representative micro-electron column, includes: an electron emitter 10 that emits electrons; a source lens 20 that forms the emitted electrons into an effective electron beam B; a deflector 30 that deflects the electron beam B; and a focus lens (an einzel lens, 40) that focuses the electron beam B on a specimen S.
The electron emitter, which is one of the major components of a conventional electron beam device, such as an electron column or an electron microscope, is classified into a FE (field emitter), a TE (thermal emitter), a Schottky Emitter as a TFE (thermal field emitter), etc. An ideal electron emitter requires efficient electron emission, high brightness, a small virtual beam size, high density current emission, low energy spread, and a long lifespan.
There are two types of micro-electron columns: a single electron column that includes an electron emitter, and electron lenses for controlling an electron beam generated from the electron emitter; and a multi-type electron column that includes a plurality of electron emitters, and a plurality of electron lenses for controlling electron beams generated from the plurality of electron emitters. The multi-type electron column is classified into the following categories: a wafer-type electron column that is similar to a semiconductor wafer and includes an electron emitter having a plurality of electron emitter tips provided on one substrate, and an electron lens formed by layering a plurality of lens layers, the lens layers being provided with a plurality of apertures on one substrate; a combination-type electron column that controls electron beams emitted from respective electron emitters in a manner similar to a single electron column, with lens layer having a plurality of apertures on one substrate; and another type electron column that is formed by arranging single electron columns in one housing. Herein, the lenses of the combination-type electron column may be used in the same manner as those of the wafer-type electron column, except for the difference that the electron emitters are separately divided.
The above described micro-electron column is a major tool in the fields of electron beam lithography, electron microscopes, etc., where electron beams are used to inspect a semiconductor hole, such as a via hole or a through hole.
Further, in the field of electron columns or in other application fields of electron beams, only when an electron emitter is accurately aligned at the center of an optical axis of an electron lens (particularly, a source lens), a device or equipment using an electron column or an electron beam can show the best performance. Further, the higher the density of the electron beam that is scanned toward a specimen along the optical axis is, the higher the performance can be. In other words, resolution can be increased with higher electron density. Thus, in order to increase the density of the electron beam, it is important that as many electrons as possible enter the aperture of the source lens.
In particular, in the fields of semiconductors and displays, the structures of elements of a device, such as a semiconductor or display, are becoming microscopic while the overall size of the manufactured product is becoming larger. As a technology and a device for precisely and rapidly processing, measuring, and inspecting such a microstructure, a variety of devices using an electron beam are increasingly required. Accordingly, a multi-type electron column capable of improving productivity is increasingly required, and accordingly an electron emitter corresponding to the multi-type electron column is also increasingly required.
The foregoing is intended merely to aid in the understanding of the background of the present invention, and is not intended to mean that the present invention falls within the purview of the related art that is already known to those skilled in the art.